Telstra has reported increased net profit by 8.8 per cent to $1.6 billion for the half year ending December 31.

Telstra CEO, David Thodey, said the telco invested $1.9 billion in capital expenditure during the six months, which includes its national mobile network. It has sold about 1.5 million 4G devices and he said it was on track to expand 4G coverage to 66 per cent by June.